1. Field of the Invention
The present invention relates to a substrate processing apparatus, a substrate processing method, and a program for implementing the method, and more particularly to a substrate processing apparatus and a substrate processing method which are capable of carrying out dummy processing, and a program for implementing the method.
2. Description of the Related Art
In a plasma process for manufacturing semiconductor chips, etching on thin films and CVD (Chemical Vapor Deposition) which deposits a metal on the etched thin films are carried out, by utilizing interaction between plasma and the inner wall of a vessel. In the vessel, large energy is applied e.g. by high frequency waves, so that the interaction between plasma and the vessel inner wall causes the following serious problem:
The plasma CVD grows a thin film on a substrate, but the thin film is also deposited on the vessel inner wall as well. On the other hand, the etching process shaves off the film formed on the substrate by subjecting the same to a chemical reaction, so that reaction products are decomposed by plasma and deposit on the vessel inner wall. As the plasma process is continued, the vessel inner wall is contaminated as described above, which adversely affects chemical reactions in plasma and degrades reproducibility of the process.
Therefore, in mass production plants, a vacuum vessel provided in a semiconductor chip manufacturing apparatus (substrate processing apparatus) is periodically cleaned so as to enhance the availability or rate of operation of the apparatus. In addition, a seasoning (aging) process is carried out after cleaning so as to maintain the inner wall of the vacuum vessel in a predetermined condition. To carry out the seasoning and warming-up of the apparatus, as well as to establish processing conditions for substrates included in one lot, the semiconductor chip manufacturing apparatus is provided with a function of carrying out dummy processing on a non-product substrate before execution of product processing including the plasma process.
Conventionally, to prevent occurrence of human operating errors, the dummy processing is carried out by an automatic process in which timing for the dummy processing and that for the product processing are collectively managed as a single sequence by on-line control.
In a first method for carrying out the above-mentioned automatic process, a dummy recipe for the dummy processing is linked to (registered in) a recipe for the product processing (which will be referred to as “the dummy processing recipe-linking function”), whereby the dummy processing is carried out on a non-product substrate before each execution of the product processing on a substrate lot (see e.g. Japanese Laid-Open Patent Publication (Kokai) No. 2001-176763).
In a second method for carrying out the automatic process, time intervals at which the cleaning is periodically performed are determined based on a process chamber operating parameter, such as a cumulative time period of RF (radio frequency) power discharge in a process chamber, which is set by a maintenance and management function, or the number of processed substrates (see e.g. U.S. Pat. No. 6,168,672).
In the above-mentioned first and second methods for the automatic process, however, even when the processing atmosphere in (i.e. the status of the interior of) the process chamber is stable as in the case of the product processing being continuously executed on substrate lots under the same processing conditions, a non-product substrate is subjected to the dummy processing whenever a substrate lot is subjected to the product processing or periodically, which causes not only wasteful use of non-product substrates, but also a decrease in throughput (processing capability) and hence degraded productivity in manufacturing product substrates.
Further, when the processing atmosphere in (i.e. the status of the interior of) the process chamber is unstable, it is necessary to carry out dummy processing repeatedly.